From 9572e2a3e3c255d96ddc4a16b7f8819227b8ba5e Mon Sep 17 00:00:00 2001
From: Ankit Jain <ankit.jain@xamarin.com>
Date: Wed, 16 Nov 2016 17:42:12 -0500
Subject: [PATCH] [xbuild] Handle a repeat build of a target, when building
 through ..

.. `Project.Build(..)`. For example, in:

```
	<MSBuild Projects="bar.proj" Targets="foo;foo" />
```

The second invocation of `foo`, in the *same* `Project.Build(..)` call,
would get skipped, but BuildTarget assumed that no previous `outputs`
entry existed in the `targetOutputs` dictionary.

System.Exception: MSBuild operation failed ---> System.ArgumentException: Item has already been added. Key in dictionary: 'foo'  Key being added: 'foo'
  at System.Collections.Hashtable.Insert (System.Object key, System.Object nvalue, System.Boolean add) [0x00200] in <94fd79a3b7144c54b4cb162b50fc7761>:0
  at System.Collections.Hashtable.Add (System.Object key, System.Object value) [0x00000] in <94fd79a3b7144c54b4cb162b50fc7761>:0
  at Microsoft.Build.BuildEngine.Project.BuildTarget (System.String target_name, System.Collections.IDictionary targetOutputs) [0x0007e] in <b1524340ac7e4c06b22fac1b2db62c08>:0
  at Microsoft.Build.BuildEngine.Project.BuildInternal (System.String[] targetNames, System.Collections.IDictionary targetOutputs, Microsoft.Build.BuildEngine.BuildSettings buildFlags) [0x00134] in <b1524340ac7e4c06b22fac1b2db62c08>:0
  at Microsoft.Build.BuildEngine.Project.Build (System.String[] targetNames, System.Collections.IDictionary targetOutputs, Microsoft.Build.BuildEngine.BuildSettings buildFlags) [0x0004b] in <b1524340ac7e4c06b22fac1b2db62c08>:0

Fixes: https://bugzilla.xamarin.com/show_bug.cgi?id=44549
---
 .../Microsoft.Build.BuildEngine/Project.cs    |  6 +--
 .../Microsoft.Build.BuildEngine/TargetTest.cs | 45 +++++++++++++++++++
 2 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/mcs/class/Microsoft.Build.Engine/Microsoft.Build.BuildEngine/Project.cs b/mcs/class/Microsoft.Build.Engine/Microsoft.Build.BuildEngine/Project.cs
index 33aad3dea63..b4ed8562382 100644
--- a/mcs/class/Microsoft.Build.Engine/Microsoft.Build.BuildEngine/Project.cs
+++ b/mcs/class/Microsoft.Build.Engine/Microsoft.Build.BuildEngine/Project.cs
@@ -374,10 +374,8 @@ namespace Microsoft.Build.BuildEngine {
 				return false;
 
 			ITaskItem[] outputs;
-			if (ParentEngine.BuiltTargetsOutputByName.TryGetValue (key, out outputs)) {
-				if (targetOutputs != null)
-					targetOutputs.Add (target_name, outputs);
-			}
+			if (targetOutputs != null && ParentEngine.BuiltTargetsOutputByName.TryGetValue (key, out outputs))
+				targetOutputs [target_name] = outputs;
 			return true;
 		}
 
diff --git a/mcs/class/Microsoft.Build.Engine/Test/Microsoft.Build.BuildEngine/TargetTest.cs b/mcs/class/Microsoft.Build.Engine/Test/Microsoft.Build.BuildEngine/TargetTest.cs
index 8f2aa2e7b28..d36ae158701 100644
--- a/mcs/class/Microsoft.Build.Engine/Test/Microsoft.Build.BuildEngine/TargetTest.cs
+++ b/mcs/class/Microsoft.Build.Engine/Test/Microsoft.Build.BuildEngine/TargetTest.cs
@@ -285,6 +285,51 @@ namespace MonoTests.Microsoft.Build.BuildEngine {
 			t [0].RemoveTask (null);
 		}
 
+		[Test]
+		public void TestRunTargetTwice ()
+		{
+			string documentString = @"<Project xmlns=""http://schemas.microsoft.com/developer/msbuild/2003"">
+			<Target Name=""Foo"">
+				<Message Text=""Foo ran""/>
+			</Target>
+			<Target Name=""Main"">
+				<MSBuild Projects=""$(MSBuildProjectFile)"" Targets=""Foo;Foo"" />
+			</Target>
+
+		</Project>";
+
+			var filepath = Path.GetTempFileName ();
+			try {
+				File.WriteAllText (filepath, documentString);
+
+				var engine = new Engine (Consts.BinPath);
+				var project = engine.CreateNewProject ();
+				project.Load (filepath);
+
+				var logger = new TestMessageLogger ();
+				engine.RegisterLogger (logger);
+
+				var result = project.Build ("Main");
+				if (!result) {
+					logger.DumpMessages ();
+					Assert.Fail ("Build failed, see the logs");
+				}
+
+				Assert.AreEqual(1, logger.NormalMessageCount, "Expected number of messages");
+				logger.CheckLoggedMessageHead ("Foo ran", "A1");
+
+				Assert.AreEqual(0, logger.NormalMessageCount, "Extra messages found");
+				Assert.AreEqual(0, logger.WarningMessageCount, "Extra warning messages found");
+
+				Assert.AreEqual(2, logger.TargetStarted, "TargetStarted count");
+				Assert.AreEqual(2, logger.TargetFinished, "TargetFinished count");
+
+				Assert.IsTrue (result);
+			} finally {
+				File.Delete (filepath);
+			}
+		}
+
 		[Test]
 		public void TestTargetOutputs1 ()
 		{
-- 
2.25.1